1. Field of the Invention
This invention relates to security devices and, in particular, to locks. It pertains to illumination for locks and especially to the illumination of keyholes.
2. Description of the Prior Art
It has been assumed that human beings have been using locks for several thousand years. Once keys were invented, the need for illumination for finding the keyhole in the dark became evident. Use of a pitch dipped club as a torch to illuminate the keyhole area was clumsy or worse.
Electricity has been in use for illumination for just about a century. Built in electric lights for the illumination of locks, locking areas, and of keyholes has been proposed for some years as, for example, by Sundt in U.S. Pat. No. 2,709,745 issued May 31, 1955; by Rommey, et al. in U.S. Pat. No. 2,767,303, by Jefferson in U.S. Pat. No. 2,831,959, and by Foreman in U.S. Pat. No. 3,719,821. Most of the prior art is for general electric illumination of the entire lock area, or of the area under a doorknob. To date, there have been few disclosures of illumination for keyholes, and such have been complex and expensive and generally not suited for modification of existing locks.